Elihu thomson



(No Model.)

-E. THOMSON.

ELECTED MAGNETIC BETARDING'DEVIGE. No. 272,35i Patented Peb. 13, 1883.

Fig.1-

ATTEsT: lNVENTDHi UNITED STATES PATENT Fries.

ELIHU THOMSON, OF NEW BRITAIN, CONNECTICUT, ASSIGNOR TO AMERICANELECTRIC COMPANY, OF SAME PLACE.

ELECTRO-MAGNETIC RETARDING @EVlCE.

SPECIFICATION forming part of Letters Patent No. 272,358, dated February13, 1888.

Application filed September 18, 1882.

To all whom it may concern Be it known that I, ELIHU THOMSON, a citizenof the United States, anda residentof New Britain, in the county ofHartford and State 5 of Connecticut, have invented certain new anduseful Improvements in Electro-Magnetic Retarding Mechanism, of whichthe following is a specification.

My invention consists of what term an is automatic retardation feed,accomplished through magnetic action, and adapted to any of the uses forwhich the ordinary mechanical retarding devicessuch as escapements,flies, dash-pots, Sac-are employed, but more espe- 15 cially toattaining a more perfect and steady feed of the carbons in electriclamps.

My invention consists in making the opening of a clutch, brake, detent,clamp, or equivalent device attect an electro-magnet so as to 20increase its power, thus causing the immediate closing or re-engagementof the clutch, clamp, or detent, which latter is for this purposeconnected with and operated by the electr o-magnet through theintervention of suit- 25 able mechanical devices, this action being,

however, immediately followed by a reopening of the clutch 0r detent anda repetition of the former action. I find that by the rapid opening andclosing of a suitable clutch or other 0 device in this manner I caneffect avery gradw ual movement of any mechanism, and that the inventionis specially applicable to producing a very gradual feed of thecarbon-rod for an electric lamp. It is generally preferable to 5 causethe rapid opening and closing or disengagement and re-engagement of theclutch, clamp, or other device by the short-circuiting or shunting ofthe operating-magnet when the clutch or other device is closed or inmechani- 0 cal engagement, and by the breaking of the (No model.)

net, which, when active, closes said points or surfaces, and, wheninactive releases or disengages said surfaces.

Having set forth the general principles of my invention, I will proceedto describe some of the methods that may be employed for carrying thesame into practice and some of the applications of the invention toelectric lamps.

Figure 1 illustrates in a general way the construction of a retardingmechanism made after the principles of my invention. Fig. 2 illustratesthepractical application of the invention to the carbon-rod of anelectric lamp. Fig. 3 is a top view of Fig. 2. Fig. 4 shows a specialmethod of effecting the gradual feed of a carbon in accordance withvariations in the length of arc. Figs. 5 and (5 are detailsot'construction of the lamp, Fi 4..

teferring to Fig. 1, It indicates a wheel driven by any power, (here aweight, WK) and connected with any mechanism the movement of which it isdesired to retard.

A indicates alever, mounted at I in a bracket-arm extending from thehead of an electromagnet, M, or in any other suitable support, andcarrying at one end an armature and at the other a friction toe, dog, orclamp, T, which latter, when the armature is attracted, will be drawnagainst the edge of the wheel It with a force sufficient to eitherretard or to wholly stop the movementof said wheel and any mechanismconnected with it. A spring, S, tends to disengage the friction toe orclutch T from the brake-wheel 1t, and will so disengage it when theelectro-niagnet M loses its attractive force. The electro-magnet is incircuit with any source of electricity, while the clutch T and thewheelR form, when in contactwith one another, a portion of a derived or shuntcircuit around the electro-inagnet M, as indicated, the effect ofclosing which circuit is obviously to divert the current from theelectro-magnet M and cause it to lose its power.

Theoretically the operation is as follows: When the magnet M isenergized the toe T is drawn against the wheel R, stopping its movement.This is accompanied by the closing of the short or derived circuitaround the electromagnet, which therefore loses its power, and

the spring S thereupon separates the toe T from the wheel R, thusreleasing the latter, but at the same time breaking the short or derivedcircuit, so that the magnet M is energized again and draws the toe intoengagement with the wheel, whereupon the operation is repeated. Inpractice these intermittent actions do not in reality take place to theextent of a complete disengagement, but a sufficient release of the toeT is produced to allow a gradual and slow slipping of the wheel It pastit, or, in other words, the intermittent action is so rapid as to beimperceptible. The wheel is thus under the control of an automatic"friction device, the amount of whose friction is dependent onthe moreor less complete electrical contact between the toe and the surface onwhich it bears, which contact is, so to speak, a self-regulating one.

By adjustment either of the retracting spring S or of the electriccurrent supplied to the device, the speed of movement of the wheel R orthe extent or degree of retardation may be governed;

In Figs;2 and 3 the application of the automatic retardation feed to thecarbon-carrying rod of an electric lamp is shown.

B indicates a frame, provided at its bottom and top with guide-openingsfor the carboncarrier It, while M indicates thet'eed-regulatingelectramagnet, mounted in the frame and arranged to act upon thearmature-lever A, which latter carries or actuates a releasing clutch orclamp. The latter consists of a clamp-body, C, carrying a pivotedclampingtoe, T, pivoted at I, which is made to engage with the carrierIt and prevent downward movement thereof by means of a spring, S, butwhich is disengaged from the rod so as to allow it to feed downwardwhenever the armature-lever A recedes sufticiently to cause theextension of the clamping-toe to come into engagement with the stop D.The clampbody 0 is pivoted on the lever A, and is held over by a spring,a, so that the toe T may open when its extended arm is tilted by thestop. As indicated, the toe T and the surface with which it engages forma portion of a derived or shunt circuit around the magnet M, so thatwhen they are in engagement the magnet is shunted and loses its power,thus allowing the armature to recede, the clamp to descend, and the toeto be released from the rod, so that the latter may move downward, whilesimultaneously the derived or shunt circuit is broken. The break of theshunt-circuit thus caused is immediately followed by the restoration ofthe magnets power and a consequent lifting of the clutch andre-engagemcnt thereof with the rod, the operation being rapidlyrepeated, as before explained, so that a slow feed of the rod ensues.The extent and nature of this feed are of course governed by theadjustment of the parts and by the. strength of the current supplied tothe magnet M, said supply being governed, in accordance with theconsumption of the carbons,

by any suitable arrangement of devices, or by the special arrangement tobe presently described in connection with Fig. 4.

In the arrangement of circuits shown in Fig.

2, the magnet M is represented as forming a portion of the directcircuit, includingthe carbons; but such special arrangement is by nomeans the only one that might be adopted in practice, and the path ofthe current wouldbe a matter that would admit of many variations, withvariations in the form and construction of the clutching or clampingdevices.

In Fig. 4-, R indicates a carbon-carrying rod, and E B respectively thepositive and negative electrodes of the lamp. W is a disk or wheelmounted in any suitable manner in a frame-work, and connected with agear-wheel, V, which latter engages with a rack upon the side of thecarbon-carrier It so that the movements of the latter may be governed bythe movements of the wheel or disk. \Vith the edge of the wheel or diskengages a pivoted clutch or clamping-toe, T, (seen more clearly in Fig.5.) which is mounted in a swinging frame, F, actuated through a lever,L, by a main-circuit coil 0 and core M.

The toe T is normally held in engagement with the disk by a spring, a,butis disengaged therefrom by a stop, H, whenever the frame F is loweredsufficiently. The toe T and the surface of the disk form a portion of aderived or branch circuit around the lifting-magnet O, and for thispurpose the toe is to be suitably insulated from the frame of the lampby any suitable means.

S is the ordinary retractor, acting in opposition to the main-circuitmagnet C.

K is an eleetro-magnet in a derived circuit around the electrodes E E.Its armature A carries a series of spring-contacts, electricallyconnected to one another, and arranged, as indicated in Fig. 6, to makecontact successively, when the armature is attracted, with a series ofcontacts, q, insulated from one another, but forming the terminals ofthe loops of a resistance-wire, It", or other suitable resistance devicesupported in any desired manner. As will be readily understood, as thenumber of points 1) in contact with the points qincreases the resistanceinterposed by the high-resistance wire It diminishes. The wire R forms,when contact is established between 1) and q, a portion of the derivedcircuit which passes around the coils G and includes the clutch or clampTand the clamp-surface of the disk W. S indicates the ordinary retractorapplied to the armature-lever A.

The circuits are as indicated. Starting from the point :r, themain orprincipal circuitpasscs first to the coils of the lifting andfeed-controlling magnet O, thence to the frame of the lamp and theupper-carbon carrier, to the lower carbon, and to the point 3 A secondcircuit, 5, includes between the points 00 and y the derived-circuitmagnet K. A third circuit, 6, passes to the springs 12 and (when 1) andq are in contact) to the resistance R the insulated clutching-toe T, thedisk V, and the frame of the lamp, at this point joining the main orprincipal circuit. The circuit 6 is a shunt or derived circuit to thecoils of the magnet C.

The operation will be apparent from the description already given. Thecarbons being in contact, the derived-circuit magnet K has notsufficient power to close the shunt 6, so that when the current passesthe coil 0 acts to lift the lever F and clutch T, and the latter, byrotating the dish, causes a separation of the electrodes E F. As thecarbons burn away the electro-magnet K increases in power, and bybringing the spri ngs p successively into contact with the points (1causes the cur rent to be diverted from the coils of O to an extentdepending upon the length of the are, so that the clutch is allowed tocome into contact with the stop H, and thus be disengaged from the diskW. The current thus diverted passes through the clutcl'i-surt'aces, andbeing alternately interrupted and restored, as before explained, causes,by the resultant rapid magnetization and demagnetization of themaincircuit magnet U M, a. slow retardation feed of the wheel W and thecarbon-carrier.

/ I do not limit myself to any particular construction of clutch orclamp, the essence of my invention consisting, as before explained, inmaking the closing of the clutch by a magnet cause a diversion of theenergizing-current from said magnet. Other applications of my inventionbesides to electric lamps may be readily made whenever a slow retardedmovement of any mechanism is desired,either to accord with the varyingstrength of an electric current or not.

I make no claim herein to the lamp mechanism and the varying shuntdevice shown in Figs. 4 and 5, as those are described in a priorapplication filed by me.

What I claim as my invention is- 1. The combination of a clamp, clutch,or detent, an actuating electro-i'nagnet therefor, and means for closinga derived or shunt circuit around said magnet automatically at theinstant that the parts of the clamp, clutch, or detent are brought intoengagement.

2. An automatic retardation-feed device con sisting of a clamp,clutch,or detent, an actuatthe surface of engagement of the clamp and.

wheel.

4. An automatic retardation -feed device consisting of a clamp, clutch,or detent, and an actuating elcctro-magnet therefor, having a shunt orderived circuit through the surface of engagement of the clamp, clutch,or detent.

o. The combination of a friction-wheel, a clamp engaging with andcontrolling the movement thereof, an actuating electro-magnet, and ashunt or derived circuit through the surface of engagement of the clampand wheel.

6. The combination, substantially as described, of a friction-wheel, acarbon-carrier connected thereto, a clutch device acting upon thefrictionavheel, an electro-magnet in circuit with the carbon andoperating the clutch, and a derived circuit around said electro-magnet,a portion of which circuit is through the frictional contact-surface ofthe clutch and wheel.

7. The combination of a carbon-carrier, a clutch or clamp actuated by anelectro-magnet in the main circuit, an electro-magnet in a derivedcircuit around the arc, a variable resistance device actuated thereby,and a shunt or derived circuit around the clamp electro-magnet, saidcircuit including the variable resist ance and the surfaces ofengagement of the clamp.

8. The com bination, with theleed-controlliim clectro-magnet'and theclutch mechanism actuated thereby, ot' a derived or shunt circuitpassing through a variable resistance automatically controlled inaccordance with the length of the arc, and through the surfaces ofengage ment of the clamp mechanism.

Signed at New Britain, in the county of Hartford and State ofConnecticut, this 12th day of September, A. D. 1882.

ELIEIU THOMSON.

\Vitnesses:

E. WILBUR Itrcn, B01113. HAINES, Jr.

